Abstract：With the rapid development of electrified railways in China, neutral sections and power quality problems have affected the daily operation of the traction power supply system. Fortunately, the advanced traction power supply system based on power electronics technology provides an opportunity to solve the above problems. The new hybrid advanced traction power supply system (HATPSS), based on the traction transformer and two-phase to single-phase (2AC-AC) converter, is gaining traction due to its high equipment utilization and low-cost advantages. However, as a weak link in HATPSS, the 2AC-AC converter can cause problems under port faults, such as negative sequence currents, power loss, and even system instability. In addition, due to the particularity of the HATPSS architecture and the diversity of control objectives, the traditional redundant backup scheme and emergency management have poor applicability. Therefore, considering the existing equipment's emergency operation potential and the 2AC-AC converter's topological advantages, the emergency management and control and fault recovery strategies are proposed respectively under the input/output fault conditions of the 2AC-AC converter. First, according to different fault locations and operation characteristics in the 2AC-AC converter, the fault type can be divided into two conditions: type I-output port γ fault, type Ⅱ-input port α or β fault. Under type Ⅰ-output port γ fault, the uα of the traction transformer’s secondary side can be connected to the traction network to ensure power supply for the traction load. Then, by controlling the power flow between port α and port β, the two-phase power of the secondary side can be balanced to suppress the negative-sequence current. Under type Ⅱ-input port α or β fault, the uα or uβ can be connected to the traction network according to the fault location of the input port to ensure power supply for the traction load. Adjusting the output power of port γ allows for suppressing negative sequence currents. The fault recovery strategy is initiated once the faulty port is repaired, and the HATPSS returns to healthy operation. During the process of emergency control and fault recovery, the rated power operation of HATPSS and negative sequence current suppression are realized through coordinating the existing devices of the system, such as traction transformer, grid-connected switch, two-phase-single-phase converter, and healthy traction station. To further verify the feasibility and effectiveness of the proposed emergency control and fault recovery strategies, a 20 MW simulation model and 6 kW experimental platform of HATPSS are built. Finally, the following conclusions can be drawn from the simulation and experimental analysis: (1) The proposed emergency control strategies are realized using resources, such as contact switches, traction transformers, and 2AC-AC converters, without additional hardware investment cost. (2) Under input or output faults, the fault traction station's 100% output power supply can be ensured to improve the reliability of HATPSS effectively. (3) During the process of emergency operation and fault recovery, the fault traction station remains connected to the network, and only a transient negative-sequence current is on the power grid side, effectively improving the system's power quality. The proposed emergency control idea can also be applied to modular multilevel and high- frequency isolation architectures.
[1] 高锋阳, 宋志翔, 高建宁, 等. 计及光伏和储能接入的牵引供电系统能量管理策略[J/OL]. 电工技术学报, 2023: 1-13. https://doi.org/10.19595/j.cnki. 1000-6753.tces.222089. Gao Fengyang, Song Zhixiang, Gao Jianning, et al. Energy management strategies for traction power systems with PV and energy storage access[J]. Transactions of China Electrotechnical Society, 2023: 1-13. https://doi.org/10.19595/j.cnki.1000-6753.tces. 222089. [2] 张智, 郑琼林, 张智博, 等. 一种基于复合开关的交流电气化铁路地面自动过分相装置[J]. 电工技术学报, 2021, 36(23): 4948-4958. Zhang Zhi, Zheng Qionglin, Zhang Zhibo, et al.A ground auto-passing neutral section device based on combination switches for AC electrified railway[J]. Transactions of China Electrotechnical Society, 2021, 36(23): 4948-4958. [3] 刘芸江, 胡海涛, 杨孝伟, 等. 24kV柔性直流牵引供电系统潮流计算方法与供电特性分析[J]. 电工技术学报, 2023, 38(9): 2323-2334. Liu Yunjiang, Hu Haitao, Yang Xiaowei, et al.Power flow calculation method and power distribution characteristics analysis of 24kV flexible direct current traction power system[J]. Transactions of China Electrotechnical Society, 2023, 38(9): 2323-2334. [4] 何棒棒, 高志宣, 马超. 一种基于储能系统的混合铁路功率调节器及其控制策略[J]. 电工技术学报, 2021, 36(23): 4905-4915. He Bangbang, Gao Zhixuan, Ma Chao.A hybrid railway power conditioner based on energy storage system and its control strategy[J]. Transactions of China Electrotechnical Society, 2021, 36(23): 4905-4915. [5] 罗嘉明, 韦晓广, 高仕斌, 等. 高速铁路储能系统容量配置与能量管理技术综述与展望[J]. 中国电机工程学报, 2022, 42(19): 7028-7051. Luo Jiaming, Wei Xiaoguang, Gao Shibin, et al.Summary and outlook of capacity configuration and energy management technology of high-speed railway energy storage system[J]. Proceedings of the CSEE 2022, 42(19): 7028-7051. [6] 莫少雄. 中压柔性直流铁路牵引供电系统运行域模型[J]. 电气技术, 2022, 23(10): 41-50. Mo Shaoxiong.Dispatchable region model for medium-voltage flexible direct current railway traction power system[J]. Electrical Engineering, 2022, 23(10): 41-50. [7] 黄毅, 胡海涛, 王翼云, 等. 电气化铁路列车柔性不断电过分相系统及其控制策略[J]. 电工技术学报, 2021, 36(23): 4959-4969. Huang Yi, Hu Haitao, Wang Yiyun, et al.Flexible uninterrupted phase-separation passing system and its control strategy for electrified railway trains[J]. Transactions of China Electrotechnical Society, 2021, 36(23): 4959-4969. [8] 黄文龙, 胡海涛, 陈俊宇, 等. 枢纽型牵引变电所再生制动能量利用系统能量管理及控制策略[J]. 电工技术学报, 2021, 36(3): 588-598. Huang Wenlong, Hu Haitao, Chen Junyu, et al.Energy management and control strategy of regen- erative braking energy utilization system in hub traction substation[J]. Transactions of China Elec- trotechnical Society, 2021, 36(3): 588-598. [9] 李群湛, 王辉, 黄文勋, 等. 电气化铁路牵引变电所群贯通供电系统及其关键技术[J]. 电工技术学报, 2021, 36(5): 1064-1074. Li Qunzhan, Wang Hui, Huang Wenxun, et al.Interconnected power supply system of traction substation group and its key technologies for the electrified railway[J]. Transactions of China Elec- trotechnical Society, 2021, 36(5): 1064-1074. [10] 闫晗, 舒泽亮, 姚家煊, 等. 基于三相-单相电力电子变压器的牵引供电系统负载不平衡、无功和谐波潮流分析[J]. 电力自动化设备, 2019, 39(11): 159-164. Yan Han, Shu Zeliang, Yao Jiaxuan, et al.Power flow analysis of unbalance,reactive power and harmonics in traction power supply system based on three-phase to single-phase power electronic transformer[J]. Electric Power Automation Equipment, 2019, 39(11): 159-164. [11] Li Linwei, Wu Mingli, Wu Si, et al.A three-phase to single-phase AC-DC-AC topology based on multi- converter in AC electric railway application[J]. IEEE Access, 2019, 7: 111539-111558. [12] He Xiaoqiong, Shu Zeliang, Peng Xu, et al.Advanced cophase traction power supply system based on three-phase to single-phase converter[J]. IEEE Transactions on Power Electronics, 2014, 29(10): 5323-5333. [13] 王鑫, 涂春鸣, 郭祺, 等. 电气化铁路贯通型供电系统综述[J]. 机车电传动, 2022(3): 17-28. Wang Xin, Tu Chunming, Guo Qi, et al.Review of through-type power supply system for electrified railways[J]. Electric Drive for Locomotives, 2022(3): 17-28. [14] 孟令辉, 周犹松, 闫晗, 等. 应用于贯通供电系统的两相-单相变换器直流电压纹波特性与功率均衡控制[J]. 中国电机工程学报, 2022, 42(17): 6449-6460. Meng Linghui, Zhou Yousong, Yan Han, et al.DC-link voltage ripple analysis and power balanced control for two-phase to single-phase converter in advanced traction power supply system[J]. Pro- ceedings of the CSEE, 2022, 42(17): 6449-6460. [15] 李子欣, 张航, 雷鸣, 等. 基于电力电子变压器的新型贯通式同相供电变流器[J]. 电工电能新技术, 2018, 37(5): 1-11. Li Zixin, Zhang Hang, Lei Ming, et al.New continuous co-phase traction power supply converter system based on power electronic transformer[J]. Advanced Technology of Electrical Engineering and Energy, 2018, 37(5): 1-11. [16] Wu Si, Wu Mingli, Li Linwei, et al.Analysis and comparison of MMC-based co-phase traction power supply topology for auto-transformer power supply system[J]. IEEE Transactions on Power Delivery, 2022, 37(5): 4053-4063. [17] 王鑫, 郭祺, 涂春鸣, 等. 新型混合式贯通牵引供电系统及其复合控制策略[J/OL]. 中国电机工程学报, 2024, 44(3): 981-991. Wang Xin, Guo Qi, Tu Chunming, et al.A new hybrid advanced traction power supply system and its compound control[J]. Proceedings of the CSEE, 2024, 44(3): 981-991. [18] 王鑫, 郭祺, 涂春鸣, 等. 基于模块协同的混合式贯通牵引供电装置主动容错控制技术[J]. 电力系统自动化, 2023, 47(17): 169-177. Wang Xin, Guo Qi, Tu Chunming, et al.Active fault-tolerant control technology of hybrid advanced co-phase traction power supply device based on module cooperation[J]. Automation of Electric Power Systems, 2023, 47(17): 116-177. [19] Zhou Dehong, Li Yunhua, Zhao Jin, et al.An embedded closed-loop fault-tolerant control scheme for nonredundant VSI-fed induction motor drives[J]. IEEE Transactions on Power Electronics, 2017, 32(5): 3731-3740. [20] 田旭, 周子博, 李兴城. 基于改进下垂控制的贯通同相系统负荷分配方法[J]. 电力系统自动化, 2022, 46(15): 178-186. Tian Xu, Zhou Zibo, Li Xingcheng.Improved droop control for load distribution in continuous co-phase traction power supply system[J]. Automation of Electric Power Systems, 2022, 46(15): 178-186. [21] 田航, 陈民武, 张迪雅, 等. 用于提升同相供电潮流控制器运行可靠性的开关频率动态调节方法[J]. 中国电机工程学报, 2021, 41(11): 3923-3933. Tian Hang, Chen Minwu, Zhang Diya, et al.Dynamic switching frequency adjustment for improving opera- tion reliability of co-phase power flow controller[J]. Proceedings of the CSEE, 2021, 41(11): 3923-3933. [22] 张恒, 王辉, 李群湛, 等. 采用自耦变压器供电的重载铁路牵引电缆贯通供电系统供电方案[J]. 电力自动化设备, 2021, 41(1): 204-213. Zhang Heng, Wang Hui, Li Qunzhan, et al.Power supply scheme of traction cable co-phase connected power supply system for heavy-haul railway powered by AT[J]. Electric Power Automation Equipment, 2021, 41(1): 204-213. [23] 林云志, 魏应冬, 李笑倩, 等. 川藏铁路贯通式柔性交流牵引供电系统[J]. 铁道工程学报, 2021, 38(9): 54-60. Lin Yunzhi, Wei Yingdong, Li Xiaoqian, et al.Continuous flexible AC traction power supply system in Sichuan-Tibet railway[J]. Journal of Railway Engineering Society, 2021, 38(9): 54-60. [24] Wang Xin, Guo Qi, Tu Chunming, et al.A two-layer control strategy for soft open points considering the economical operation area of transformers in active distribution networks[J]. IEEE Transactions on Sustainable Energy, 2022, 13(4): 2184-2195. [25] Dargahi V, Sadigh A K, Khorasani R R, et al.Active voltage balancing control of a seven-level hybrid multilevel converter topology[J]. IEEE Transactions on Industrial Electronics, 2022, 69(1): 74-89. [26] 何晓琼, 韩鹏程, 王怡, 等. 基于级联-并联变换器的贯通式牵引变电所系统研究[J]. 铁道学报, 2017, 39(8): 52-61. He Xiaoqiong, Han Pengcheng, Wang Yi, et al.Study on advanced cophase traction power substation system based on cascade-paralled converter[J]. Journal of the China Railway Society, 2017, 39(8): 52-61. [27] Kleftakis V, Lagos D, Papadimitriou C, et al.Seamless transition between interconnected and islanded operation of DC microgrids[J]. IEEE Transactions on Smart Grid, 2019, 10(1): 248-256.
2024, Vol. 39 
